1. Field of the Invention
This invention relates to a catalyst member for a lighter, such as a gas lighter for smoker's requisites or a pilot burner. This invention also relates to a process for producing the catalyst member for a lighter.
2. Description of the Prior Art
Techniques for lighters, such as gas lighters, have heretofore been proposed, wherein a catalyst member is located in the vicinity of a fire outlet formed at a top end of a combustion cylinder. With the proposed techniques, in cases where a flame is blown off by wind and goes out, even if a lighting operation is not carried out again by the user, re-lighting effects can be obtained with the catalyst, the temperature of which has risen to a temperature not lower than the lighting temperature due to the previous combustion. One of such techniques is disclosed in, for example, Japanese Unexamined Patent Publication No. 60(1985)-101419.
Catalytic gas lighters have also been proposed, wherein a platinum wire having a coiled shape or one of the other shapes is located as the catalyst member such that a flame may come into contact with the platinum wire. With such catalytic gas lighters, even if a flame is blown off by wind and goes out, a fuel gas will come into contact with the platinum wire, the temperature of which has risen. The fuel gas can thus be lighted again by the platinum wire.
Also, as the combustion catalyst member, it is considered to locate a flat plate-shaped catalyst member in a combustion cylinder. The flat plate-shaped catalyst member may be made by forming a porous ceramic material or a fibrous ceramic material into a paper sheet-like shape or a plate-like shape, dip coating the paper sheet- or plate-like material with a catalyst solution, such as a chloroplatinic acid solution, thermally decomposing the dip coated layer, and thereby forming platinum particles on the paper sheet- or plate-like material.
Further, as for a platinum wire having a coiled shape, which is utilized as the catalyst member (catalyst wire) in a catalytic gas lighter, such that the lighting performance of the catalyst wire may be enhanced, catalyst wires having various dimensions and shapes have been proposed. For example, in Japanese Unexamined Patent Publication No. 2(1990)-178519, a catalytic fire outlet for a lighter is disclosed, which is provided with a coiled catalyst wire having a wire diameter falling within the range of 0.10 mm to 0.25 mm, a coil outer diameter falling within the range of 1.0 mm to 2.0 mm, and the number of turns falling within the range of 6 to 10. Also, Japanese Unexamined Utility Model Publication No. 3(1991)-71257 discloses a gas combustion catalyst for a lighter, which has an elliptic coiled shape and in which a diameter of a wire material falls within the range of 0.8 mm to 0.20 mm, a coil longer diameter falls within the range of 1.8 mm to 2.8 mm, a coil shorter diameter falls within the range of 0.8 mm to 1.8 mm, the number of turns falls within the range of 3 to 6, and a coil pitch falls within the range of 0.4 mm to 1.0 mm. Further, Japanese Unexamined Utility Model Publication No. 3(1991)-121353 discloses a gas combustion catalyst for a lighter, which has a circular coiled shape and in which a diameter of a wire material falls within the range of 0.8 mm to 0.20 mm, a coil outer diameter falls within the range of 1.4 mm to 2.2 mm, and a coil pitch falls within the range of 0.4 mm to 1.0 mm.
However, the platinum wire, which is ordinarily used as the catalyst member in the gas lighters, or the like, in which a fuel gas can be lighted again with the catalyst member, is very expensive. Therefore, in cases where the platinum wire is used as the catalyst member, the problems occur in that the cost of the gas lighter cannot be kept low. Accordingly, it is difficult to use the expensive platinum wire in gas lighters which must be cheap, such as disposable gas lighters.
Specifically, in order for a platinum wire to constitute a catalyst member, it is necessary to use a platinum wire having a diameter of approximately 1.0 mm and a length of approximately 35 mm. The weight of the platinum wire having such a size is as large as approximately 5.9 mg, and therefore the material cost by itself becomes high. Also, in cases where the platinum wire is used as the catalyst member, only the surface of the platinum wire, which comes into contact with a gas flame flow, can exhibit a catalytic reaction, and the region inward from the surface of the platinum wire cannot contribute as the catalyst. Also for this reason, the amount of platinum used cannot be kept small.
With the catalyst member comprising a carrier, which is constituted of the flat plate-shaped porous ceramic material or the flat plate-shaped fibrous ceramic material, a fuel gas burns at the position of the catalyst member, and no flame is obtained at a position above a combustion cylinder. Therefore, the problems occur in that sufficient functions for lighters cannot be obtained.
Specifically, the effects of the catalyst in lighters are that, at the time at which a combustion flame has been blown off by wind and has gone out, the catalyst has been heated to a temperature not lower than a temperature, at which a catalytic combustion reaction of the fuel gas can occur, and the catalyst can again light a subsequent gas flow. Also, in cases where the lighter is used for lighting cigarettes, or the like, or for other purposes, it is desirable that a fuel gas burns with a flame at the top end of the combustion cylinder in order to facilitate the lighting of cigarettes, or the like.
When a fuel gas burns with a flame at the top end of the combustion cylinder, it often occurs that the flame is blown off by wind and goes out. In such cases, the catalyst automatically re-lights cigarettes, or the like, in the manner described above. However, with the flat plate-shaped catalyst member described above, the volume of the catalyst member located at the top end of the combustion cylinder becomes large. Therefore, when most of the gas flow comes into contact with the catalyst member, the gas undergoes the catalytic combustion at the reaction temperature of the catalyst at the position of the catalyst. As a result, the combustion with red heat of the catalyst proceeds, and combustion with a flame cannot be obtained at the top end of the combustion cylinder.
In order for the combustion with a flame to be obtained, it is necessary that the contact area of the catalyst member is small with respect to a gas flow. In such cases, most of the gas flow passes through the position of the catalyst without coming into contact with the catalyst and burns at a position above the top end of the fire outlet, and the combustion with a flame is thereby obtained. At this time, a portion of the gas flow comes into contact with the catalyst and undergoes catalytic combustion, and the temperature of the catalyst member is thereby kept at a temperature not lower than the catalytic reaction temperature. Therefore, even if the flame at the region of the combustion with the flame is blown off by wind and goes out, the fuel gas can be lighted again by the catalyst. Also for this reason, the linear catalyst member constituted of a platinum wire is used ordinarily, and a structure is employed wherein the linear catalyst member is located with a small area appropriate with respect to the gas flow area in a combustion cylinder. For example, as for platinum or platinum alloy catalyst members employed in ordinary gas lighters, a wire having a diameter falling within the range of approximately 0.1 mm to approximately 0.2 mm is coiled so as to have a coil diameter of approximately 2.5 mm and a length of a coiled part falling within the range of approximately 3 mm to approximately 5 mm and is used in this form.
Further, with the porous, flat plate-shaped catalyst member described above, the heat capacity of the catalyst member becomes large and, as a result, the drop in the temperature of the catalyst after the fire has been extinguished becomes slow. Therefore, there is the risk that a gas, which has leaked from the fuel gas tank of the lighter, is lighted by the catalyst member after the fire has been extinguished. Specifically, if the heat capacity of the catalyst member is large, a long time will be required for the temperature of the catalyst member to drop to a temperature not higher than the temperature, at which the oxidation reaction of the fuel gas begins, after the fire has been extinguished. In such cases, there is the risk that a leakage gas, a residual gas, or a gas, which has leaked from the fuel gas tank of the lighter due to an erroneous actuation of a gas lever when the lighter is accommodated in a pocket of the user, comes into contact with the hot catalyst member is thereby lighted again.
The re-lighting characteristics of a catalyst wire also vary in accordance with the dimensions and the shape of the catalyst wire. However, with the conventional catalyst wires having the dimensions and the shapes described above, a sufficient re-lighting performance cannot always be obtained. Thus a need exists for an even further improvement in the dimensions and the shape of a catalyst wire.